Title: Experiment 1: Microscopy of Living Microbes
Purpose: To prepare students to familiarize themselves with the lab equipment such as the microscope, square glass, cover slips, etc.; to facilitate students to observe the pond water; and enable them to discern and identify the microbes as bacteria, algae, fungi, or protozoa within the pond water. Additionally, this lab experiment will permit students to observe and distinguish the yeast suspension from the other microbes.
The student acquired the fundamental skills in which to properly handle lab equipment and execute an experiment. By examining the pond water with the 40X lens, the student was able to distinguish and identify the protozoa with cilia: colpidium, which was recognized by its unique oval shape, resembling a peanut, with small hair-like particles comprising the entire surface, and the vascular plant, which was discrete due to its array of composition of cells. By examining the pond water with the 100X lens, the student was able to differentiate and classify 1) the cyanobacteria: nostoc due to its distinctive S shape and beads with surrounding cells, 2) two nematodes (phylum nematoda) parallel to one another (the nematodes appeared as slender worms, colorless, and encompassed of cells), and 3) the cyanobacteria: anabaena, which was blue-green in its feature with long filaments of cells (resembling a seaweed structure). By examining the yeast suspension with the 40X lens, the student observed millions of budding yeast cell structures. The student was able to discern between the various structures of pond water microorganisms, such as cilia and algae, and the yeast suspension cellular material.
1. What is Brownian motion and why is it generally seen when bacteria are observed in liquid media? Some bacteria, perhaps many in your presentation did not display Brownian motion. Why is that? Brownian motion is a non-directional movement triggered when cells are blasted by water molecules. Brownian motion is generally seen when bacteria are observed in liquid media primarily by the production of gas that bacteria yields, which is converted into liquid fluids. Thus, some bacteria, many in the experiment presentation, did not display Brownian motion because of the lack of energy of the system and the absence of flagella that impels bacteria to move voluntarily. 2. How can Brownian motion be distinguished from motility?
As mentioned previously, Brownian motion is a non-directional movement triggered when cells are blasted by water molecules whereas motility is the capability of an organism to independently move either towards or away from a specific stimulus. Therefore, Brownian motion is distinguishable from motility due to it being a false movement while motility enables organisms to transfer by means of flagellum, endoflagella, or axil filaments. 3. What are flagella? What is the difference between bacterial flagella and eukaryotic flagella? Flagella are long protein structures responsible for most type of prokaryotic motility and also propel cells through liquid. Bacterial flagella, which are also referred to as prokaryotic flagella, are smaller than eukaryotic flagella and have a simple structure, are made up of protein flagellin that provides a mechanism of motility, are proton driven, and have a rotatory movement. On the other hand, eukaryotic flagella have a larger and more complex configuration, are composed of tubulin that delivers a mechanism of locomotion, are ATP driven, and have a bending movement. 4. In wet mount preparations, is it possible to see eukaryotic flagella? Prokaryotic flagella? In wet mount preparations, it is possible to see eukaryotic flagella, but it is not possible to see prokaryotic flagella. 5. Does crystal clear pond water contain living bacteria? What about air? Your finger? All things that are not sterile do contain living bacteria such as pond water, air, and fingers.